Siberian tigers are the largest of all cats. In historic times, the tiger's range was vast, covering much of Asia. Over the last century, they've experienced an almost total population crash, and at least 97% of those tigers have gone.

Often referred to as the gray ghost or ghost of the mountains, this animal's rarity and elusiveness was legendary. In the past, it was known as the ounce, but today we've settled on the name snow leopard.

Pumas are also known by the names of cougar or mountain lion. However, these cats are only distantly related to lions. They're much more closely related to cheetahs. And while pumas are often found in mountains, they're just as at home in the lowlands, dense forests, treeless pampers, or deserts.

Lions differ from all other cats in that they are highly social, forming prides of up to 35 animals. There are now thought to be fewer than 15,000 lions remaining in Kenya's Masai Mara, a drop of 75% in 50 years.

Like most big cats, the leopard is a master of secrecy. It's one of the hardest of all big cats to see, let alone observe. This is mainly because leopards need absolute invisibility to hunt. This is why they're such good climbers and why they evolved to be so incredibly secretive.

The first jaguar scientists struggled to go anywhere near their subjects. But times have changed. There are now a couple of places in the world where seeing a wild jaguar is a possibility rather than a dream.